Proceedings of the 16th IEA ES TCP International Conference on Energy Storage (ENERSTOCK 2024)

Thermal energy Storage has received widespread attention for its role in integrating variable solar energy. Latent heat thermal energy storage with phase change materials (PCMs) is regarded as a promising technology. In this study, two novel metal-based microencapsulated PCMs with melting temperatures of 577 °C and 520 °C are analysed for their application in the 650 °C next-generation solar power plant. Five storage units with different Al-Si to Al-Cu-Sivolume ratios (1:0, 0:1, 1:1, 2:1) and height/diameter ratios (3:2, 2:3) are designed and benchmarked under the actual operating conditions, with the charge and discharge cut-off temperatures set for the return loop at 376 °C and 456 °C.The results show that the case with single Al-Si PCM leads to higher average outlet temperature, which is good for steam generation, while the case with single Al-Cu-Si PCM shows higher storage capacity. The thermal performance of the cascaded models with two PCMs exhibit a compromise between high outlet temperature and high storage capacity. The height/diameter ratio of 3:2 shows the best performance considering outlet temperature and stored heat capacity.